Air tool improvement



June 22, 1965 e. G WALKER ETAL 3,190,183

AIR TOOL IMPROVEMENT 2 Sheets-Sheet 1 Filed May 10, 1962 Gearye 6' Wa/A'er xficfiara f [CA mar;

INVENTORJ BY QOQMA awm ATTORNEY June 22, 1965 WALKER ETAL 3,190,183

AIR TOOL IMPROVEMENT 2 Sheets-Sheet 2 Filed May 10, 1962 INVENTORJ BY EO-ev n-KQ -k Afro/FIVE United States Patent Bessemer Corporation, Mount Vernon, Ohio, :1 cor-p0 ration of Ohio l Filed May 10, 1962, Ser. No. 193,780

12 Claims. (Cl. 91-80) Our present invention relates in general to tools of the type employing as the motor elements thereof a unit characterized by the use of pressure fluid operating against a vaned rotor, which devices shall be identified hereinafter as air tools. a

It long has been common practiceto employ pressure fluid, primarily air, to provide the operative force in a variety of tools and particularly in hand tools such as drills, screw drivers, nut runners, impact wrenches, grinders and similar items. Many industries employ such tools in substantial numbers for a wide range of purposes, and our present invention is adaptable for use in virtually all types.

The following explanation establishes the background against which our contribution is to be viewed. A conventional vane type air motor has an accentrically mounted rotor carried within a housing. Air circulated through the housing between properly situated inlet and exhaust ports operates against radially extensible vanes mounted on the rotor to produce energy which may be applied by a work performing element connected thereto. However, the vanes wear against the internal surface of the housing, and both the vanes and the rotor may wear against the surfaces which define the ends of the air circulation chamber. Thus, over an ordinary service life, the tool steadily decreases in efliciency as more air escapes by the worn surfaces instead of operating with full etfect against the exposed surfaces of the vanes.

The surfaces defining the air circulation chamber within a conventional air motor are integral with the housing and other expensive machined elements such as hearing housings. In order to obtain new wearing surfaces, it is necessary to replace the major element or elements on which such surfaces are formed, so tool repairs are quite costly and time consuming. Consequently, one who employs a large number of air tools of various types is required to maintain a complete stock of all component parts of the tools within his inventory, provide skilled workmen to perform repairs, provide spare tools in order to replace out-of-service tools while they undergo repair, provide test equipment to insure that repairs have'been properly performed and the tools properly reassembled and adjusted, all in addition to bearing the substantial cost of replacing major machined parts order to rea turn worn tools tofull efiiciency.

The foregoing is in sharp contrast to the advantages flowing from our invention. We propose a tool in which the motor is completely self-housed so that when a tool requires repair following a normal service life, the motor may be quickly and easily replaced with a new or rebuilt unit, fully assembled and tested and ready for immediate operation. This feature alone represents a substantial departure from conventional practice and would produce a major saving to a tool user. However, our invention goes further, for we propose a line oftools in which the major machined elements of the motor do not bear the surfaces which are exposed to wear. Instead, the air circulation chamber within which the rotor operates is defined by a replaceable cylinder-and closed at each end by a replaceable wear plate. These relatively inexpensive inserts may be replaced at a fraction of the cost of the major elements of the motor, and this improve- 3,19%,183 Patented June 22, 1965 ice ment in conjunction with the self-housed design of our unit will render possible an entirely new approach to the problem of air tool repair and maintenance.

The advantages of the procedure which will result from tools embodying our invention can be summarized in the following terms. The user is relieved of the expense and responsibility of maintaining a large spare parts inventory and skilled repair personnel, as well as the need for spare tools and elaborate test equipment. His spare parts inventory need comprise but a group of self-housed motor units adequate in size and number to meet only the immediate requirements of the tools in use in his operation. A relatively inexperienced or unskilled workman can quickly effect a motor change, and as the replacement unit will already be fully assembled and tested, it can be relied upon to immediately return the tool to full efficiency. The worn unit then can be returned to the manufacturer or to a major repair point where it can be quickly and easily rebuilt by changing the bearings, rotor vanes,.and replaceable inserts, all of which may be considered expendable parts.

From'the foregoing, it will be appreciated that the primary object of our invention is to provide a cartridge type or self-housed air motor unit which may be readily replaced within any air tool of proper standardized design to accommodate such a motor. 7

Another major object of, our invention is to provide a self-housed motor constructed so that the wearing surfaces thereof can be readily and economically removed and replaced with inexpensive inserts.

An additional object of our invention is to provide a tool which lends itself to quick replacement of worn subassemblies by relatively unskilled or inexperienced personnel.

Yet another object of our invention is to provide an air motor unit which upon return to the manufacturer or other suitable major repair point can be quickly and economically returned to maximum efliciency through the replacement of wear surfaces with inexpensive inserts, thereby avoiding the necessity'for scrapping expensive machined parts.

A further object of our inventionis to provide a replaceable' sleeve for ready insertion and removal from an air motor, such sleeve having a wearing surface therewithin of a synthetic material characterized by a relatively smooth surface and good wearing qualities.

Our manner of accomplishment of the above described objects, as more fully described hereinafter, is illustrated in the attached drawing of an air motor driven die grinder. This unit has been chosen to exemplify our invention because of its relative simplicity, but it is to be understood that the principles described herein are readily applicable to, and are proposed for use in all air motor driven tools.

In the drawing: 7

FIG; 1 is a cross section of a tool embodying our invention taken along lines 11 of FIG. 2;

FIG. 2 is a cross section along line 2-2 of FIG. 1;

FIG. 3 is a developed view of the tool of FIG. 1, show-.

generally an air tool encased withina main body 11 and a spindle housing 12 releasably connected thereto. Pressure fluid is admitted to the tool through the inlet connector 13 which is adapted for attachment to an air hose or similar element to supply pressure fluid.

I side faces of 30. In our'self-housed motor unit, it is relatively simple performing el ment.

' age 14 into chamber 15. By depressing the throttle lever 16, the throttle valve seat 17 is removed from its seat 18, whereby the pressure fluid is admitted into throttlechamber 19 and thence through passage 20 into the annular manner so theparts'are operablyconnected and readily space 21Within the main bocly It'is apparent that'the flow of the pressure fluid' is controlled by the throttling assembly.

Carried within the main body 11 of the air tool is the motor unit which is identified generally byreference nu-' meral 22and 'is best shown in FIGS. 1 and '4. The" unit is housed by a housing 23 and co nduit means 24 formed therewithin is partially definedby a replaceable cylindrical sleeve insert 25. 'A series of air inlet ports 26 through the sleeve 25 admits pressure fluid from the con duit 24 to an air circulationchamber 27 defined-by the sleeve 25 (seeFIG. 2').

It will be apparent that there is no necessity for precise angular alignment between the self-housed motor unit 22 j and the main body 11. Theipassage 24 always will be in communication with the annular space .21, and. pressure fluid willbe directed to the circulation chamber 27 by one end by bearing means 29, and 'at the other end by.

bearing means 30.

28 which Mounted on the rotor 28 are radially eXtensiblevanes 31 which move outwardly in response to'the centrifugal force of rotation for sliding contact with the internal surface of sleeve 25. A pressure fluid circulation chamber 27 is subdivided into sectorsby the-vanes, and the pres .sure fluid entering through theinlet ports 26 acts against the vanes exposed theretoto drive the rotor about its own axis.

" Substantially opposite the inlet ports 26 (approximately 180 of rotation of the rotor) exhaust ports: 32

and-3'3. are provided through the sleeve 25 and, housing'23 respectively as shown in FIG. 2. From theseaslots, th

exhausted air moves into the annulus 34 between the'main body 11 and the'housing 23, and thence through passages 35, annulus 36, and. passage 37', from which point it escapes to the atrnosphere through the end of the tool for lateral ports which may be provided for, such purpose;

The motor unit just described rotates at a high rate of 'speed, up to 30,000 revolutions 'per minute, and'the vanes are in sliding contact with the internal surface of the sleeve 25. It is the Wear between such elements :Which ultimately impairs the efliciency of operation ofthe motor to such a point that repair is'required. Further, theends of the vanes and a portion of the rotor. arein contact with the members which defineithe'ends of the fluid circulation chamber, andaccor'ding to our invention, these take" the form of substantially'flat disc-like wear plates38 and 39.. From the foregoing,iit can be seen, that the points of i .wear in the motor will 'be the bore of sleeve 25, the inthe plates 38 and 39 and the bearings 29 and to disassemble the motor and replace these parts with new 7 parts which are inexpensive to manufacture"; 'We con- ,template that such disassembly will be by the manufacturer or ata major repair station Whichi equipped with spindle 40 whichis supported by bearings 30 and,41within bearing casing .42. However, it :is to b'e understood:

that various gear trains or similar elements may besubstituted for the spindle40in1theevent reduction, is desired. Thus, as employed herein, the term spindle is intended .to includeany type 'of,.transm'ission element adapted to apply the output of the motor to a work The end of thespindle 40 which is 28 may be splined as at 43 or joined in any convenient separable.

. When it is desired to replace. the motor, unit within the Y tool, the spindle housing 12 1's removed from the main body 11, and the entire motor and spindle unit removed. @The spindle unit may be detached from the housing 23 and secured to a new or rebuilt motor, or both the motor and spindle may be replaced. Thereafter, upon return to an adequate repair facility, the parts indicated herein-i above 'to be expendable may be removed and replaced. a

When anew sleeve .25 is to be inserted into housing 1 23, it is necessary that; the inlet and exhaust port 26 r and 32 .be placed in proper radial alignment with the conduit24 and exhaust ports-33 in'the housing. This; is acbearing spacer 47 is similarly notched.

H Asc'rew 48 and spacer: means in the form of washer 49 are received within the end of rotor 28 and secure the 1 bearing means 29 in proper position prior to assembly.

of the rotor within the housing. Thereafterithe wear plate 39 and spacer means 50 are slipped into position within the housing, and the bearing casing 42. joined thereto. Finally the spindle housing 12 is secured to'the, i 'main body 11 to complete reassembly.- i FIGIS shows an optional feature of our invention which may be incorporated into the sleeve 25. We presently coni template that the sleeve be-formed of a suitable metal or alloy to provide good wear qualities, but recent develop, 'ments inthe field of synthetics, indicate the feasibility. of. 'bondingffa relatively thin. layer: ofs'uch material to. the. internalsurface of the sleeve. A material such as Teflon will provide a hard smooth surface oiferingrclatively little. f frictional. resistancelto sliding contact with the vanes 31, and insure a satisfactory service life; Thus the liner151 within-sleeve 25 is of a'synthetic rubber or resinous mar 'terial which lends itself to the demands 'of our unit.

Many obvious changcsfand special applications of the principles of ourinvention will occur to one'slrilled in the 1 art of-airtool design. Consequently, it is dcsired to pro-. tect by" letters patent all such modifications as fall within 1 'a rotatable spindle disposed-within-said body adapted for having attached thereto a work performing elei went, and

- a self-housed motor unit carried within the confines of 'the body and operatively connected'to the spindle, said motor unit comprising a housing, a r

' cation with the pressure fluid circulation means to admit pressure fluid into the housing,

' v [a cylindrical sleeve insert-removably disposed within.

1' the confines of' the housing iof the motor unit,

, saidsleeve insert having a plurality of spaced apart presi sure fluid inlet ports in communication wit-hthe con:

duit -means,- i j V saidhousing and said slee've insert being provided with a rotor eccentrically mountedwithin the sleeve insert for rotation relative'thereto,

V fbearing'means'disposed adjacent each end portion -of the cylindricalsleeve insert'for enabling the rotorto be rotated relative thereto, i

joined to the rotor conduit means disposed in the housing in communiexhaustports for exhausting pressure fluid therefrom,

5. said rotor having a plurality of vane members carried thereby for generally radially extensible movement relative thereto with the vane members ngaging the sleeve insert to impinge circulating pressure fluid against the vane members and impart rotation to the rotor, substantially flat disc-like wear plates removably disposed within the confines of the housing in engagement with the cylindrical sleeve insert and the vane members of the rotor, and spacer means for preventing the wear plates from having any engagement with the bearing means. 2. The combination of claim 1 in which said pressure fluid circulation means comprises an annular space within said tool body, and said conduit means is in communication therewithpwithout regard to radial alignment therebetween.

3. The combination of claim 1 in which said tool body is longitudinally separable to facilitate removal therefrom of said spindle and said motor unit.

4. The combination of claim 1 in which said spindle is releasably engageable with said housing to retain and position said rotor and wear plates therewithin. 7

5. The combination of claim 1 and an exhaust conduit in communication with said exhaust ports, said exhaust conduit comprising an annulus defined by an inner wall of said body and an outer wall of said housing in communication with the atmosphere through said tool body. 6. A self-housed pressure fluid actuated motor unit' adapted to be disposed within a body of a tool,

said motor unit comprising a housing,

conduit means disposed in th housing in communication with pressure fluid circulation means to admit pressure fluid into the housing, a t

a cylindrical sleeve insert removably disposed within the confines of the housing of the motor unit,

said sleeve insert having a plurality of spaced apart pressure fluid inlet ports in communication with the conduit means, 7

said housing and said sleeve insert being provided with exhaust ports for exhausting pressure fluid therefrom,

a rotor eccentrically mounted within the sleeve insert @01- rotation relative thereto,

bearing means disposed adjacent each end portion of the cylindrical sleeve insert for enabling the rotor to be rotated relative thereto, a

said rotor having a plurality of vane members carried 0 spacer means for preventing the Wear plates from having any engagement with the bearing means.

7. The combination of claim 6 in which said housing is substantially closed at one end and is open at the other end for removal and replacement of the elements carried therewithin.

8. The combination of claim 6 and a replaceable liner secured within said sleeve insert, said liner being formed of a relatively hard and smooth surfaced synthetic ma- '11. A pressure fluid actuated motor comprising a housing adapted for accommodation within the body of an air tool, said housing being substantially closed at one end and open at the other end, conduit means within said housing to admit and exhaust pressure fluid therefrom, a replaceablefcylindrical sleeve insertable from said open end and carried within said housing, pressure fluid inlet and exhaust ports through said sleeve in communication with said conduit means, a rotor eccentrically mounted within said sleeve for rotation relative thereto, a plurality of vane members carried by said rotor and radially extensible relative thereto as permitted by said sleeve Whereby circulating-pressure fluid imparts said rotation to said rotor, replaceable Wear plates positioned within said hous ing adjacent the ends of said sleeve, a longitudinally projecting lug on the end of said sleeve toward said closed end of said housing, and mating recesses Within said wear plate adjacent thereto and said housing to radially align said sleeve and said wear plate relative to said housing.

12. The combination'of claim 11 and a replaceable liner bonded to the internal surrace of said sleeve, said liner being formed of a relativelyh-ard and smooth surfaced synthetic material;

References Cited by the Examiner UNITED STATES PATENTS 1,"167,1*54 .1/16' 'Darlington 9180 1,167,995 1/16 Hauer 9ll--80 2,575,524 '1 1/51 Mitchell 91 2,715,889 8/55 Sturrook 91--80 Q,7'38,755 13/56 Smyser 9 1-80 2,903,97-1 9/59 Coll-ins 10 3- 1114 3,049,103 8/62 Dum-m Ill-99 3,080,851 3/ 63 Zizka 12/1 34 FRED E ENG-ELTHALER, Primary Examiner.

B. WILKINSON, SAMUEL LEVINE, Examiner's. 

1. AN AIR TOOL COMPRISING A TOOL BODY, PRESSURE FLUID CIRCULATION MEANS FOR ADMITTING PRESSURE FLUID INTO THE BODY AT A CONTROLLABLE RATE, A ROTATABLY SPINDLE DISPOSED WITHIN SAID BODY ADAPTED FOR HAVING ATTACHED THERETO A WORK PERFORMING ELEMENT, AND A SELF-HOUSED MOTOR UNIT CARRIED WITHIN THE CONFINES OF THE BODY AND OPERATIVELY CONNECTED TO THE SPINDLE, SAID MOTOR UNIT COMPRISING A HOUSING, CONDUIT MEANS DISPOSED IN THE HOUSING IN COMMUNICATING WITH THE PRESSURE FLUID CIRCULATION MEANS TO ADMIT PRESSURE FLUID INTO THE HOUSING, A CYLINDRICL SLEEVE INSERT REMOVABLY DISPOSED WITHIN THE CONFINES OF THE HOUSING OF THE MOTOR UNIT, SAID SLEEVE INSERT HAVING A PLURALITY OF SPACED APART PRESSURE FLUID INLET PORTS IN COMMUNICATION WITH THE CONDUIT MEANS, SAID HOUSING AND SAID SLEEVE INSERT BEING PROVIDED WITH EXHAUST PORTS FOR EXHAUSTING PRESSURE FLUID THEREFROM, A ROTOR ECCENTRICALLY MOUNTED WITHIN THE SLEEVE INSERT FOR ROTATION RELATIVE THERETO, BEARING MEANS DISPOSED ADJACENT EACH END PORTION OF THE CYLINDER SLEEVE INSERT FOR ENABLING THE ROTOR TO BE ROTATED RELATIVE THERETO. SAID ROTOR HAVING A PLURALITY OF VANE MEMBERS CARRIED THEREBY FOR GENERALLY RADIALLY EXTENSIBLE MOVEMENT RELATIVE THERETO WITH THE VANE MEMBERS ENGAGING THE SLEEVE INSERT TO IMPINGE CIRCULATING PRESSURE FLUID AGAINST THE VANE MEMBERS AND IMPART ROTATION TO THE ROTOR, SUBSTANTIALLY FLAT DISC-LIKE WEAR PLATES REMOVABLY DISPOSED WITHIN THE CONFINES OF THE HOUSING IN ENGAGEMENT WITH THE CYLINDRICAL SLEEVE INSERT AND THE VANE MEMBERS OF THE ROTOR, AND SPACER MEANS FOR PREVENTING THE WATER PLATES FROM HAVING ANY ENGAGEMENT WITH THE BEARING MEANS. 